Electron discharge device



June 19, 1934. w, G, URMSQN ELECTRON DISCHARGE DEVICE Filed Jan. '7, 1931 am y INVENTOR fl i'ZZl'a/Iz Gib/7150M BY fiio ATTORNEY Patented June 19, 1934 UNITED V STATES 1,953,254 ELECTRON DISCHARGE DEVICE William G. Urmson, Hamden,

Conn, assignor, by

mesne assignments, to Radio Research Laboratones, Inc., a corporation of Delaware Application January 7, 1931', Serial No. 507,117

' 11 Claims. (01. 250 27.5)

My present invention relates to improvements in electron discharge devices.

One object of the invention is to provide a compact and efiicient co-ordination of the electrodes in rectifier and radio tubes and the like, whereby they are maintained in proper space relationship against accidental dislocation and whereby they constitute a unitary structure adapted to be readily supported in the tube, and whereby the respective electrodes may be readily connected to the lead-in wires from the press of the tube.

Another object is to provide a unitary structure wherein provision is made for a heater type of cathode comprising a high resistance heater energizable with high voltage and low amperage current directly from a source having voltage comparable to that of a house lighting circuit; and wherein provision is made for an electron emissive cathode in connection with the heater so as to be heated thereby to emissive temperature. The heater type cathodes referred to include, for example, those disclosed in the copending applications of present patentee Urmson Serial No. 507,116 filed Jan. 7, 1931, and David A. Barnett Serial No. 507,133 filed Jan. 7, 1931.

Other objects and advantages of the invention will become apparent as this specification proceeds.

With the aforesaid objects in view, the invention consists in the novel combinations and arrangements of parts hereinafter described in their preferred embodiments, pointed out in the claims, and illustrated in the drawing wherein like parts are designated by the same reference characters throughout the several views.

In the drawing, Fig. 1 is a combined sectional and elevational view of a three electrode radio tube embodying my invention; Fig. 2 is a perspective view of one of the insulating caps detached from the construction shown in Fig. 1; Fig. 3 shows a heater cathode of the type disclosed in Urmson Serial No. 507,116; Fig. 4 shows another type ofheater-cathode as disclosed in Barnett Serial No. 507,133; Fig. 5 is still another form of heater-cathode disclosed in Urmson Serial No. 507,116; Fig. 6 shows the grid element detached from the construction shown in Fig. 1; Fig. 7 shows the plate elementdetached from the construction shown in Fig. 1; and Fig. 8 shows a two-piece insulating cap construction as a sub.- stitute for the one-piece insulating cap of Figs. 1 and 2, the dotted lines in this figure serving to indicate the relation in a fragmentary way of the various electrodes to this cap construction.

The advantages of the invention as here outlined are best realized when all of its features and'instrumentalities are combined in one and the same structure, but useful devices may be provided embodying less than the whole.

It will be obvious to those skilled in the art to which this invention appertains that the same may be incorporated in several different constructions. The accompanying drawing, therefore, is submitted merely as showing preferred illustrative embodiments of the invention but without limiting the invention thereto.

Describing now the devices of the drawing embodying, as stated, preferred illustrative forms of the invention, 1 is the glass envelope of an electron discharge tube, 2 is the stem, 3 the'press. The tube in Fig. 1 happens to illustrate a threeelectrode radio tube having combined heatercathode element, a grid and a plate. These three elements are operatively supported insulated from one another to constitute a unitary structure designated in general 4 as follows: The plate 5 (compare Fig. 7) consists of a thin sheet of metal or Woven wire bent into cylindrical form with its free ends wrapped around and weldedto a' wire 6 sufiiciently heavy to support the entireunitary structure from the press 3; The open ends of the tubular element thus formed are closed by two discs or caps 7 made of any suitable refractory insulating material. These discs are alike in construction and are held in place against theends of the tubular electrode by means of lugs 5 from the plate bent around the'edge of the discs tohold them in place. Each disc or cap (compare Fig. 2) has on its inner face two concentric annular ridges 7 and 7 the inner ridge enclosing a center recess and the inner and outer together forming an annular recess. The endsof the cylindrical heater-cathode element 8 are seated in the center recess of the caps; and the ends'of the hollow cylindrical grid 9 are seated in the annular recess of the caps.

The combined heater-cathode element may take various forms but in general constitutes a-high resistance heater combined with a cathode or itself constitutes the cathode by being made of emissive material or by being coated with emissive material. 7

Some of the specific forms which this heatercathode may take are as follows: It may consist, as in the aforesaid Urmson case, of a closely wound coil 8 of fine wire (Figs. 1 and 3) such as tungsten, supported on a cylinder 8 of refractory insulating material so as to constitute a high resistance coil which, when energized by voltages comparable with house lighting voltage, carries a few milli-amperes current and is heated to a temperature sufficient to cause electron emission from the emissive material with which the coil is coated. The terminals 8 of the coil extend respectively through minute center holes 7 in theinsula-ting caps 7 for connection with the lead-in'wires FF coming through the press of the tube. The upper terminal 8 connects with a horizontal wire l6 supported by a wire 16 from the press.

Another form of the heater-cathode element, as in the aforesaid Barnett case, consists of: the high resistance wire coil 8? .(Fig. 4) but supported inside of a refractory insulating cylindrical shell 8 instead of on the outside. In this form,.a metallic conductor 8 constituting the cathode is supported on the outside of the insulating shell so as to be separated thereby from thecoil. This outside conductor is made of an electron cmissive .metal orqis made of av metal coated with electron einissive material, and said conductor ma take the form of a windingor be a thin cylindrical plate .or tube. Inany event, as above, the combined heater-cathode is supported axially-within the ,unitary structure by having. its ends seated in thediscs-or caps '7. The aforesaid cathode 8 may .be electrically distinct from the heater coil'and may have its own separate terminal connected with its own lead-in wire. In that event, the ends of the heater coil will have their :own separate lead-in wires. Ont-he otherihand, the heater coil may be connected inserieswith' the cathode as in Fig.:4,in which event there will be only two lead-in: wires to the heater-cathode element.

Still another form of heater-cathode element may comprise, as in said Urmson case, a rod 19 (Fig. 5) of an electrically conductive but high resistance compositionof materials,such as carborundum, siloxicon, carbon and other ingredients in the proper proportion to give a high resistance comparableto that 20f theaforesaid heater -coil of somewhat similar 1 dimensions. This rod may then be coatedwith a thin layer of electronemissive material 10.

Indeed, the 1 combined heater-cathode may take other formsbut the above are deemed to besufficiently illustrative.

The-grid 9 when present may consist of a-cylindrical, open mesh structure supported between the caps 7 by having .itsendsgseated in the annular recess thereofconcentric with-the heatercathode. The particular-form illustrated (Figs. 1 and 6) consists of a cylindrical wire coil 9 to one side of which is weldedawire 12 parallel to the axis of the coil. Thus, this wire 12 integrates the coil and supports its-various spirals inspaced apartrelationship. The ends of this wire-project through minute, holes 17 :in the caps convenient for connection with the lead-in wire G for the grid.

It will be seen that the correlated and united capsand electrodes "form, a .unitary structure supported from the press on the wire 6 welded to the side of the hollow :plate electrode 5. This wire also serves to connect with the lead-in wire P for the; plate.

The insulating discs or caps each may be made of: two pieces as shown =in 'Fig. .8 but otherwise the essential structure is the same as the onepiece form above described. Thus, referring to this Fig. -8, the inner piece consists of a cylindrical-walled cup 14 and the outer piece consists of a circular base 15 having an annular ridge 15 located on-one facenear its outer periphery.

wing. through .holes adjacent ends areseated about the lindrical plate 5 has its open ends closed by the The base of the cup-shaped piece l4 fits down into the space within the annular ridge of the outer piece.

To use this two-piece form of cap, two of the. cups 1% are fitted over the ends of the heatercathode 8 and are secured thereon by means of any suitable refractory insulating cement with the terminals of the heater'element coming out of axial holes through the bottom of the cups. The heater-cathode element is then supported with these cups seated within the annular ridge of the other part and with the terminals of the elements. passing through axial holes therein.

The grid .9 surrounds the heater-cathode element as before with .its supporting rod 12 passthe inner side of the annular ridge. The grid is held from contact withthe=heatercathode because its cylindrical cup parts 14. The cyparts I 15,. and these are heldyin place as: before by the bent over lugs fr of theplate.

Of course, in rectifier tubes the grid 9 (Fig. 1).wil1: :be omitted. 1

-What I claim is:

1. In an electron discharge-tube, a-unitary structure supported therein comprising a hollow plate electrode, insulatingcaps-closing the ends of the hollowyplate, said. caps-having. a center recess and a surrounding annular .recess; a heater-cathode element supported axially'within the hollow plate with its ends seated :inrthecenterrecesses of the caps; and=a hollow grid-surrounding-the heater-cathode-with its ends contained in: the annular recesses of the caps.

2..In an electron discharge tube, -a-unitary structure supported therein-comprising 8;!110110W plate electrode, insulating caps at the-endspof the hollowplate, said capsv having annular grooves, a' heater-cathode element supported by said caps in. axial-positionwithinthe hollow plate; and a hollow grid supported by the grooves in said caps in surrounding position relatively to. the heater-cathode, the capshaving orifices forqthe passage of the terminals .offthe'heater-cathode" and grid.

3. In an. electron discharge-tuba. a :unitary structure supported therein comprising a hollow plate electrode, insulating caps at theends of the'hollow plate, said caps having annular grooves, a heater-cathode element, supported; by said capsin axial position within the hollow plate; and a hollow grid supported by thegrooves in said capsin surrounding.position'relatively tothe heater-cathode, said grid comprisingta 30 wire coil to one side of which iswelded aterminal wire parallel with. the axis of the-coilfthe caps having holes receiving through them 1 the ends of said grid terminal wire.

4. In an electron discharge tube,. a :unitary structure supported therein comprising .a cylindrical plate electrode, insulating capsat the ends of said cylindrical -p1ate,'.'sa'id caps havingannular grooves, a heater-cathode element supported by said caps in axial position within the cylinlfl drical plate; a hollow grid supported by the grooves in said caps in surrounding position relatively to the heater-cathode; and means for supporting said unitary structure comprising a sufficiently heavy wire projectingfrom thepress of the tube and welded to the side of the cy-lindrical plate.

5. In an electron discharge tube, ..-a :unitary structure a supported therein comprising .a L hollow plate electrode, a hollowgrid, insulating caps 15 closing the ends of the hollow plate, said plate having bent up lugs engaging the caps securing them in place; said caps having a center recess and annular grooves to receive the ends of said grid; and a heater-cathode element supported axially within the hollow plate with its ends seated in the center recesses of the caps.

6. In an electron discharge tube, a unitary structure supported therein comprising a hollow plate electrode, a hollow grid electrode, insulating caps closing the ends of the hollow plate, said plate having bent up lugs engaging the caps securing them in place, said caps having a center recess and annular recesses in said grooves to receive the ends of said grid; a heater-cathode element supported axially within the hollow plate with its ends seated in the center recesses of the caps; and means for supporting said unitary structure comprising a wire projecting from the press of the tube welded to the side of the hollow plate.

7. In an electric discharge device, a cathode, a tubular grid, a tubular anode, and insulator caps on both ends of said anode, said caps having concentric grooves for spacing the cathode grid and anode.

8. In an electric discharge device, a tubular cathode, a tubular grid, a tubular anode, and

of insulating members and a plurality of electrodes,including cathode, anode, and control grid, said insulating members having a number of parallel projections thereon to separate the ends of said electrodes, and means including said projections for maintaining all of said electrodes in concentric spaced relation.

11. An electric discharge device comprising an enclosing receptacle, insulating blocks within said receptacle, said blocks having a plurality of similar projections, and cathode grid and anode electrodes seated in said blocks and maintained in spaced relation by said projections.

WILLIAM G. URMSON.

DISCLAIM ER 1,963,254.W'lliam G. Urmsom Hamden, Conn. ELECTRON DISCHARGE DEVICE. Patent dated June 19, 1934. Disclaimer filed April 19, 1935, by the assignee, Radio Research Laboratories, Inc. Hereby enters this disclaimer to the following claims of said patent, to Wit: Claims 2, 3, 4, 7, 10 and 11. [Ofiic'ial Gazette May 14, 1985.] 

